Wire controlled flasher switch



Dec. 23, 1969 c. F. FREY 3,486,153

WIRE CONTROLLED FLAS-HER SWITCH Filed Aug. 5. 1967 INVENTOR. I CLEON FREY BY wwwwzfluz/fla m United States Patent I U.S. Cl. 337-133 1 Claim ABSTRACT OF THE DISCLOSURE A snap switch having a contact-bearing snap vane ofcomparatively large area with a thermally extensible wire having one end connected directly to the vane and normally holding the vane in an open-contact buckled condition. A coiled continuation of the wire providing a series resistance therewith enabling application of line voltage across the wire and resistor combination for heating the wire, to thereby elongate it sufiiciently to enable the vane to snap back to contact-closed condition providing a shunt path through the vane across input terminals and across the series combination of wire and resistance, permitting the cooling thereof. Means mounting the resistance generally parallel to and adjacent the vane, the Wire being connected directly to the vane, both facilitating heat dissipation to the vane, with the large area thereof and fanning action enabled by the mounting thereof to rapidly dissipate heat and produce the desired clicking noise.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to wire-controlled flasher switches and more particularly to one having a minimal number of parts but characterized by excellent heat transmission, noise, and load-handling characteristics.

DESCRIPTION OF THE PRIOR ART In vehicles it has been found desirable to provide means for continuously flashing at least two lights at the front end and two lights at the rear end during certain types of operation of the vehicles. Examples include local delivery trucks, ice cream vending trucks, mail trucks, stalled automobiles, and highway maintenance vehicles. While various flasher switches are known for vehicle turn signals, the operation of four or more bulbs of comparatively high wattage in a continuously flashing manner imposes loads which such flasher switches are unable to handle. For commercial vehicles in particular, where noise levels are typically comparatively high, it is desirable that any flasher switch employed be able to produce a comparatively loud clicking noise to remind the operator that the flashers are functioning.

While it is desirable to have excellent load-handling characteristics and desirable noise-making features, it remains important that such devices be of reliable yet simple and of inexpensive construction. Therefore, while heated wire controlled switches are known as indicated by'US. Letters Patent No. 2,761,931 to Schmidinger, and other patents cited therein, the present invention is considered superior to those devices, particularly in the respect of load-handling noise-generation, and cost.

SUMMARY Described briefly, in a typical embodiment of the present invention, a non-conductive base is provided with a pair of terminal blades mounted thereto and projecting in one direction therefrom, and a metallic cylindrical closure mounted thereto and projecting in the opposite a direction. Within the closure and virtually co-extensive therewith, is a comparatively large rectangular vane of 3,486,153 Patented Dec. 23, 1969 spring metal, normally held in a buckled condition by a Wire which is connected thereto at one end and which is provided with an adjustable anchor near the other end. A coiled extension of the wire serves as additional resistance in series with the active (thermally expanding) length of wire to limit somewhat the current flow through the wire. It provides ballast so that line voltage from the terminal blades can be applied across the combination of the resistor and heatable wire. Application of line voltage heats the wire, causing extension thereof which permits the vane to snap to a contact-closed condition, shunting the terminals through the vane and permitting the resistor and wire to cool. Upon cooling, the wire again pulls and snaps the vane to the contact-opened condition, whereupon heating of the wire again commences and a new cycle is initiated.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front view of a typical embodiment of the invention.

FIG. 2 is a right side view thereof in the wire-heated closed-contact condition.

FIG. 3 is a rear view thereof.

FIG. 4 is a left side view thereof in the normal opencontact condition.

FIG. 5 is a top view thereof in the wire-heated closedcontact condition.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, a typically circular, non-conductive base 11 of phenolic or other material is provided with a terminal blade 12 and terminal blade 13 affixed thereto by suitable tabs to enable plugging the assembly into an appropriate socket receptacle. Terminal blade 13 provides attachment means for a first Support member 14 of stamped metal construction and retained securely on the base 11 by the tabs which serve both to mount the terminal 13 and secure it, as well as support member 14, to the base 11. The support member 14 includes an upstanding leg 16 which has a pair of rivets 17 affixed to the upper end portion thereof and securing a generally elongated rectangular vane 18 thereto, this vane being made of spring metal and tending to normally have a straight linear appearance from the side as shown in the drawings and a slight bow as viewed from above. Because of the offset at 19 in the upstanding leg 16 of the support member, both the lower portion 21 of the vane below rivets 17 and the upper portion 22 thereof above the rivets, are free to move back and forth in the direction of the arrows 23 and 24 in a manner which will be described.

As shown in FIG. 2, the vane has a contact 26 mounted on the backside thereof near the lower margin of portion 21. Note that this is the point on the vane which is both nearest the base and most remote from rivets 17. Note also that the rivets 17 are attached to the vane near the right-hand margin 27 thereof so that the entire portion to the left of rivets 17 is supported in cantilever fashion as is the entire portion above and below the rivets 17 as suggested above with reference to the arrows 23 and 24 in FIGURE 2. Normally contact 26 is engaged with a contact 28 aflixed to a second contact support member 29 which is afiixed t0 the back of the upstanding leg 16 of support member 14 by the four tabs shown in FIGURE 3, and insulated therefrom by the insulator strip 31, FIG. 5. Member 29 is electrically connected to terminal 12 by spot welding to its arm 29a the conductor 32 which is typically a copper wire with a loop 32a therein from the weld point 32b to one of the tabs of terminal 12, the loop permitting adjustment of the contact 28 back and forth in the direction of the arrow 23 as desired,

without clifficulty. This adjustment can be accomplished by simply bending the arm 29a of the support member 29, the aperture 2% therein providing the reduced cross section facilitating this bending.

Although the crown or how in the vane 18, and which it adopts when no external forces is applied thereto, would normally urge contact 26 against contact 28 as shown in FIGURE 2, a straight portion 33 of wire is wound at its upper end 34 around a tab 36 integral with and projecting upwardly from the upper end of the vane 18, while a loop of the wire is secured in a bead 37 of glass or other suitable material, this bead being seated in an aperture 38 in a finger 39 provided on the support member 14. The straight portion 33 of this wire or tensioned member, anchored between these two points, is short enough so that it pulls the upper end of the vane downwardlycausing it to buckle into the bowed form identified at 42 in FIGURE 4. The buckling effect moves the lower margin in the direction of the arrow 23 (FIG- URE 2) to the position shown in FIGURE 4, maintaining separation between the contacts 26 and 28. The Width of this space 43 between the contacts is determined by the position of contact 28 as well as by the location of the stop finger 44 extending upwardly from the support member 14 and integral therewith and engaging the front face of the vane opposite the contact 26.

A further portion of the wire extends in a coil 46 from the bead 37 upwardly and parallel to the front face of the vane and diagonally across to a support at 47 at the upper end of the continuation of wire 32 from the point where it is spot welded to the arm 29a. Thus the straight and coil portions 33 and 46 are typically made of a single piece of fine wire which, in effect, is continuously connected across terminals 12 and 13, the copper wire 32 providing the connection to terminal 12; rivets 17, and support member 14 providing the connection to terminal 13.

The whole assembly upward from the base 11 is enclosed by a metallic, typically aluminum, closure 48 rolled onto the base 11 and rather fully occupied by the vane 18 as shown in FIGURE 1, the upper and side marginal edges of the vane being proximate the inner walls of the closure. The unit is typically mounted by the terminal blades 12. and 13 into a socket indicated schematically at 49 with one conductor of the socket being supplied from a positive terminal of battery 51 through switch 52, while the other blade is connected to the negative battery terminal. This can be done through one or more bulbs 53, two of which might be at the front of a vehicle and two at the rear of the vehicle. Clearly other arrangements might also be used but this illustration emphasizes that this switch is voltage operated and can operate one or more lamps. For example, it can flash one or ten lamps at the same rate. It can be used to replace any other type flasher. It can be used for both turn signals (two, three or four lamps) and also for emergency signals up to ten lamps on the same flasher.

In operation, the wire portion 33 normally maintains contacts 26 and 28 separate, so that the only circuit path from terminal 12 to terminal 13 is through the coiled and tension portions 46 and 33 respectively of the wire. This heats both the coil and the wire, and the heating of the portion 33 causes it to elongate. At a certain point during the elongation thereof, the residual stress imposed by the wire in buckling the vane to the condition shown in FIGURE 4 is effective to unbuckle the vane by snap action, whereupon it returns to the condition shown in FIGURE 2 urging the contact 26 against contact 28. Then the electrical path between the terminals is from terminal 12 through -wire 32, support arm 29a, contact 28, contact 26, vane 18, rivets 17, and support member 14, to terminal 13. So the vane is in shunt across the wire portions and the full load of the bulbs is handled through the vane and contacts. Meanwhile, the shunting of the wire portions enables the cooling thereof whereupon the portion 33 again shortens. The shortening thereof pulls the upper edge of the vane down until the vane again snaps back to the initial position against the stop member 14 as shown in FIGURE 4.

The timing of the flashing can be varied by bending the wire support finger 39 up or down in the direction of the arrow 54 in FIGURE 2. Because of the fact that the vane is comparatively large and, while securely afiixed to the support member 14 by the two rivets, has only a small portion thereof directly aflixed to the support member and that portion is offset near the edge of the vane, rather large excursions of the majority of the area of the vane do occur as it snaps back and forth in response to the heating and cooling of the wire portion 33. This serves to cause considerable disturbance of the air at the faces and edges of the vane, providing good heat transmission to the air and good noise generation. The imposition by the wire, of a bow at to the normal bow of the vane, the latter being in a section parallel to the base. enables the production of a loud click both when the vane is buckled and when it unbuckles. Accordingly, as the switch operates, a substantial fanning effect is provided and, with the edges of the vane immediately adjacent to the internal walls of the metallic closure, heat and sound transmission to the closure and from there to the atmosphere is readily obtained.

The excellent heat transmission to the closure readily dissipates the heat developed at contacts 26 and 28, which can be considerable when five to ten lamps are lit, the current approaching twenty amperes with the ten lamp maximum load. The connection of the upper end of the wire portion 33 to the vane also serves to quickly dissipate the heat from the wire as desired, immediately after the contacts close.

From the foregoing description, it is believed apparent that the present invention achieves the desired objectives with a minimum of parts, and inexpensive construction. While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention, reference being made to the appended claims.

The invention claimed is:

1. A hot-wire type flasher switch comprising a base plate with electrical terminal members extending from one side of the base, an electrically conductive support member extending from the other side of the base and electrically connected to one of the terminal members, said support member having a first extending leg portion, a flexible vane having a transverse curvature and extending generally parallel to said first leg portion of the support member and being rigidly secured thereto intermediate the ends of the vane and adjacent one side margin, a tensioned thermal expansion wire fastened to the end of the vane remote from said base and to said support member for buckling the vane longitudinally at normal temperature but permitting the vane to snap out of buckled condition at an elevated temperature, said support member having a second extending leg portion extending to a position adjacent the side margin of the vane opposite said rigidly secured side margin and adjacent the end of the vane nearest said base plate, said second leg portion functioning as a stop defining the maximum buckled position of said vane end nearest the base plate, said support member having a sidewardly extending element electrically insulated from the support member, said sidewardly extending element carrying a fixed electrical contact adjacent to but on the opposite side of said vane from said stop provided by said second leg portion, a cooperating electrical contact carried by said vane and adapted to engage said fixed contact when said vane has snapped out of buckled condition, and wires electrically connecting another of said terminal members with said fixed contact and with the end of said tensioned Wire remote from its attachment to said vane, whereby upon imposition of an electrical potential of sufficient magnitude across said terminal members said tensioned Wire will elongate permitting said vane carried contact to engage said fixed contact thereby electrically shunting said tensioned Wire to again separate said contacts to repeat the contact engagement and disengagement cycle.

References Cited UNITED STATES PATENTS 2,977,440 3/1961 Lessner 337-140 3,236,972 2/1966 Welsh 337-135 FOREIGN PATENTS 689,292 6/1964 Canada. 1,244,275 2/ 1959 France.

OTHER REFERENCES German printed application DAS 1,125,034, March 0 196 2, R. Bosch.

BERNARD A. GILHEANY, Primary Examiner D. M. MORGAN, Assistant Examiner US. Cl. X.R. 337135 

